Observation of Kink Instability as Driver of Recurrent Flares in AR 10960

TL;DR

This study observes kink instability in active region NOAA 10960, linking helical twists in coronal loops to recurrent solar flares, demonstrating how magnetic instabilities can drive flare activity.

Contribution

It provides observational evidence connecting kink instability with recurrent flares in a specific active region, highlighting the role of helical twists in flare triggering.

Findings

Helical twists of ~3 and ~2 turns observed before flares.

Kink instability likely triggers recurrent flares.

Twists associated with positive polarity sunspot.

Abstract

We study the active region NOAA 10960, which produces two flare events (B5.0, M8.9) on 04 June 2007. We find the observational signature of right handed helical twists in the loop system associated with this active region. The first B5.0 flare starts with the activation of helical twist showing ~3 turns. However, after ~20 minutes another helical twist (with ~2 turns) appears, which triggers M8.9 flare. Both helical structures were closely associated with a small positive polarity sunspot in the AR. We interpret these observations as evidence of kink instability, which triggers the recurrent solar flares.